Gwen's notes on how to be a particularly annoying depressed person:

• Quote a lot. Especially from Waiting for Godot.
• When someone asks you "How's it goin'?" or "How ya doin'?", answer, "Oh, not so good," à la Sarah in High Fidelity.
• Walk around scowling and sighing a lot.
• Mention your therapist whenever possible, especially as a total non sequitur.
• Have dizzy spells. Make a big deal out of them.
• Wear baggy, dark-colored clothes and don't wash or brush your hair.
• Zone out in class, lectures, meetings, whatever. Do not attempt to curtail or hide this behavior.
• When someone calls you up and asks if you want to do something, tell them you're just not up for it. If they ask why, be coyly evasive for a while before you finally confess that your "mood disorder" has been acting up.
• Act listless even when you know you're feeling something. Express emotions only via withdrawal or rage.

I'm sure I could think of a lot more, but I have to go write a paper about something I'm not qualified to write about.